Quite an interesting article here on Wiki. I had no idea. To take heat like this they must have been very effective. When I was about 14 I was camping with my family and listened to a Sally Ann band. The Oompa type. Brass drums etc. It had a deep effect on me even at that young age. As I listened I found the Holy Spirit speaking to me and calling me although at the time I didn't really understand it. Its interesting one of main opposition actually got saved.